The protective cover for the underhood fuse center was omitted. Without this cover, the positive terminal bolt on the fuse block is exposed and can contact the insulated negative battery cable. If the insulation on the negative cable becomes sufficiently worn, an electrical short circuit can occur between the positive terminal and negative cable resulting in extremely high current flow.
Dealers will inspect these vehicles for the presence of the protective cover and, if necessary, install a protective cover to the underhood fuse center.